<![CDATA[Polyester-based composites are widely used engineering materials in manufacturing industries because of their cost-effectiveness and ease of fabrication. However, the inherent brittleness of polyester necessitates the incorporation of reinforcement materials to improve its mechanical performance. This study aimed to evaluate the effects of natural fibers and inorganic fillers on the mechanical and thermal properties of polyester-based composites through a systematic literature review. Data were collected from nine selected experimental studies covering various natural fibers, including corn, pineapple, coconut coir, kenaf, jute, and sisal fibers, as well as inorganic fillers such as kaolin, pumice powder, and nanofillers. The analysis focused on tensile strength, flexural strength, impact resistance, thermal stability, and thermal conductivity while considering variations in composition, fabrication methods, and fiber surface treatments. The findings indicate that each type of fiber and filler has an optimum composition at which the best performance is achieved. Fiber surface treatment substantially influences the quality of interfacial bonding between the reinforcement and polyester matrix, whereas inorganic fillers contribute significantly to improving the thermal properties of the resulting composites. Overall, the appropriate selection of reinforcement type, composition, and surface treatment is essential for optimizing the performance of polyester-based composite materials.]]>
